Mechanical lockout for ultrasonic surgical instrument

An ultrasonic surgical instrument, comprising:

• (a) a handle assembly configured to support an ultrasonic transducer, wherein the handle assembly includes:
• (i) a seat portion configured to removably connect to a shaft assembly,
• (ii) a yoke operatively connected to the seat portion and configured to translate between a first yoke position and a second yoke position, and
• (ii) a trigger selectively pivotal to actuate from an intermediate trigger position to an inward trigger position for activating a portion of the shaft assembly with the trigger in the inward trigger position, wherein the trigger is further selectively pivotal from the intermediate trigger position to an outward trigger position for locking movement of the trigger;
• and
• (b) a mechanical lockout assembly including a closure lever link pivotally connected to each of the trigger and the yoke,
• wherein selective movement of the trigger from the intermediate trigger position to the outward trigger position selectively transitions the closure lever link to a locked configuration such that the closure lever link and the yoke prevent movement of the trigger from the outward trigger position to the intermediate trigger position, and
• wherein selective movement of the yoke from the first yoke position toward the second yoke position via the seat portion is configured to selectively transition the closure lever link to an unlocked configuration such that the trigger moves from the outward trigger position to the intermediate trigger position thereby allowing the trigger to be selectively actuated toward the inward trigger position.

A method of transitioning a mechanical lockout assembly of an ultrasonic surgical instrument between a locked configuration and an unlocked configuration, the ultrasonic surgical instrument including:

• (a) a first modular assembly configured to support an ultrasonic transducer, wherein the first modular assembly includes:
• (i) a seat portion configured to removably connect to a second modular assembly, and (ii) an operator input selectively movable to actuate from a first position to a second position for activating a portion of the second modular assembly with the operator input in the second position;
• and (b) the mechanical lockout assembly operatively connected between the seat portion and the operator input and configured to selectively transition from the locked configuration to the unlocked configuration when the second modular assembly fully seats and removably connects to the seat portion of the first modular assembly, wherein the mechanical lockout assembly in the locked configuration prevents selective movement of the operator input to the second position, and wherein the mechanical lockout assembly in the unlocked configuration allows selective movement of the operator input to the second position, the method comprising:
• (a) fully seating the second modular assembly to the seat portion thereby transitioning the mechanical lockout assembly from the locked configuration to the unlocked configuration and allowing selective movement of the operator input to the second position.